This invention relates to a method of treatment of water in order to inhibit corrosion and diminish mineral deposition.
Typically, if mineral deposition can be diminished or eliminated, the advent of corrosion can also be diminished. Thus, this invention deals primarily with the elimination of, or the significant decrease of, mineral deposition from aqueous systems. Minerals which are easily deposited from water can cause problems. For example, it is not difficult to remember mineral build-up on leaky water faucets, boiler tubes, cooling towers, humidifiers, water pipes, air conditioners, fish tanks, washing machines, sinks, auto radiators, hoses, cisterns and many other water systems, especially those systems which operate by losing some water to the atmosphere which causes the mineral contained in the water to concentrate. Everyone has experienced the distasteful sight of the buildup of such mineral deposits and, aside from the aesthetics, many have experienced the lack of performance of certain aqueous systems because of the deposits of such minerals, for example, the diminished capacity of heat exchangers.
It seems that one way to prevent the deposition of such minerals is to eliminate such minerals from the water, but this could become very time consuming and costly. Moreover, quite often, such minerals are purposely added to aqueous systems to control corrosion; therefore, total elimination of the minerals is not the answer either. A better method, and a more economical method, appears to be the stabilization of the minerals in the aqueous systems such that they do not readily deposit from the aqueous systems.
Many compounds have been suggested for this use. Such compounds include those which can be added to aqueous systems and which react with depositable minerals or, in the case of corrosion control, such compounds are reacted with the minerals and added to aqueous systems. Such compounds are, for example, shown in U.S. Pat. No. 3,121,692 as being useful in antifreeze formulations. Disclosed therein are aminofunctional siliconates or derivatives of such siliconates wherein the nitrogen atom is substituted with hydrocarbon groups containing hydroxyl, amido, ester, hydrocarbonoxy or cyano functionalities. Another patent, U.S. Pat. No. 3,198,820, deals with copolymers of soluble silicates and carboxylic acid functional siliconates, which siliconates may be monocarboxylic acid functional or polyacid functional. U.S. Pat. No. 3,234,144 discloses a process for inhibiting corrosion using amine functional siloxanes. U.S. Pat. No. 3,341,469 deals with a process for inhibiting corrosion using a copolymer of soluble silicate and dihydroxyl or polyether functional siliconates. Other disclosures of similar applications appear in U.S. Pat. No. 4,370,255, issued Jan. 25, 1983 (alkali siliconates of silylalkyl phosphonates); U.S. Pat. No. 4,344,860, issued Aug. 17, 1982 (carboxyalkylsubstituted nitrogen or sulfur-containing siliconates) and U.S. Pat. 4,352,742, issued Oct. 5, 1982, U.S. Pat. No. 4,354,002, issued Oct. 12, 1982 and U.S. Pat. No. 4,362,644, issued Dec. 7, 1982 (arylalkyl and aliphatic silicone sulfonate-silicate copolymers). Further, there is disclosed in U.S. Pat. No. 3,723,333, issued Mar. 27, 1973, the use of compounds having the formula ##STR1## and a water-soluble, complex-forming compound which contains at least one phosphonate or N-dimethylenephosphoric acid group, wherein X is OH or NH.sub.2 and R is an alkyl radical of from 1 to 5 carbon atoms.
Finally, in U.S. Pat. No. 4,418,195, issued Nov. 29, 1983, there is disclosed the use of novel thiazines as corrosion inhibitors.
None of the above references, however, describe the compositions or the process of this invention.